1. Field of the Preferred Embodiments(s)
This invention generally relates to a pointing device for controlling the positioning, movement and operation of a cursor on a display screen. Specifically, there is a collar mounted pointing stick with a resistor based strain gages mounted thereon.
2. Description of the Related Art
Various devices are well known for controlling cursor movement over a computer display screen of a computer and for signaling a choice of computer command identified by the position of the cursor on the display screen menu. One such device is a "mouse" which has a ball on its underside rolled over a horizontal surface, with the x- and y-axis components of movement being sensed and transmitted through a connecting cable to a serial input port of the computer. The signal to the computer is varied by the amount and direction of movement of the mouse ball, and causes the cursor on the display screen to have a corresponding movement. Two "mouse" or "click" buttons located on the top of the mouse at the forward end permit the computer operator to enter a selection or other command to the computer (the command typically being shown by the position of the cursor on a displayed menu) upon pressing one or the other or both buttons, depending upon the software associated with the device. Such a device, which is separate from the computer console and keyboard and requires a connection to a computer port, requires a flat, horizontal surface, and for operation of the mouse, the computer operator must completely remove one hand from the computer keyboard.
Another cursor controlling the signaling mechanism is a "joystick" which like the mouse is completely separated from the computer console and keyboard. The joystick is typically an elongated stick that extends upwardly from a base connected to the computer console by means of a cable. The joystick is operated by tilting the upstanding stick in various directions to cause the cursor or other display element to move in a direction and usually at a speed corresponding to the direction and pressure exerted on the stick by the computer operator. The operation of a joystick, however, frequently requires that both hands be removed from the computer keyboard, one hand to hold the base while the other manipulates the joystick. A "click" button is usually located on the joystick. Although a mouse or a joystick can be used with a portable "laptop" or "notebook" size computers, such devices are cumbersome, must be carried separately and connected to the computer before use, and are not suitable for operation during travel.
Another type of cursor controlling device is a "trackball." This device, which in essence is an inverted mouse, includes a rotatable ball mounted within a housing. The ball is rotated by a finger, thumb or palm of the computer operator, and the x- and y-components of movement are sensed and input into the computer to cause corresponding movement of the cursor across the display screen. "Mouse" or "click" buttons are usually located on the trackball housing, although with some models the selection signal is input by pressing the "enter" key on the standard keyboard. This type of pointing device has been found useful with portable computers because it can be temporarily affixed to one side of the computer case for manipulation by one hand of the computer operator. However, though trackball devices can be removably attached to the computer case, they still require attachment before use and removal after use and they do not have an ergonomically positioned set of "click" buttons.
Manufacturers of portable laptop computers, recognizing the need for placing the cursor controlling device in a permanent and more convenient location, installed a small stubby, button-like joystick centrally around the keys of the computer keyboard, specifically at the juncture of the "g," "h" and "b" keys of the standard "QWERTY" keyboard. The joystick, also known as a pointing stick, was sensitive to lateral pressure, the amount and direction of which were sensed and input into the computer to cause movement of the cursor, and the speed and direction of cursor movement corresponded to the amount and direction of pressure on the joystick. That manufacturer also provided two upwardly extending "mouse" or "click" buttons immediately below the space bar.
Despite the advantages of each type of cursor control, none have been easily adapted to personal digital assistants (PDAs), palmtop computers, and the like. Specifically, current pointing stick designs are too tall to apply to PDAs. Uniquely, one major current manufacturing technology requires strain gages to be located on the pointing stick. Strain gages are devices that sense the amount and location of applied pressure placed upon the pointing stick. The sensed pressure creates electrical output signals used to direct the cursor on a display device. The maximum amount of created strain on the pointing stick is at the base of the pointing stick where it attaches to the supporting substrate. Thus, the ideal location for a strain gage is at the maximum strain point - at the base of the stick. However, current manufacturing capabilities place strain gages a required distance above the previously attached substrate surface. Therefore, the minimum height of the stick is fixed so that enough strain can be created at the location of the elevated strain gages for proper operation. This minimum height far exceeds the height maximum for application of a pointing stick onto a PDA keyboard. Based on this strain gage minimum height location criteria, the pointing stick cannot be shortened more than present designs for proper operation. Therefore, there is a need for a pointing stick, which uses side mounted strain gages, that is short enough to fit into a PDA keyboard.
3. Description of Related Art
Examples of patents related to the present invention are as follows, and each patent is herein incorporated by reference for the supporting teachings:
U.S. Pat. No. Re. 35,016, is a three-axis force measurement stylus.
U.S. Pat. No. 5,489,900, is a strain sensitive columnar transducer for a data entry keyboard contains a column upstanding from the keyboard.
U.S. Pat. No. 5,473,347, is a computer pointing device for controlling the positioning, movement and operation of a cursor on the display screen of a computer.
U.S. Pat. No. 5,407,285, is an apparatus for use in a computer keyboard for cursor control is disclosed.
U.S. Pat. No. 5,521,596, is a sensor device placed either underneath a key cap or a key on a keyboard or between two keys on a keyboard so that cursor movement may be carried out from the keyboard itself.
U.S. Pat. No. 4,876,524, is an isometric control device or the like of the type having an elastic beam and strain gauges attached to the surface of the beam characterized by at least a first group of three strain gages each having an operative axis thereof inclined with a single predetermined angle with respect to the main axis of the beam, and the strain gauges disposed at a first predetermined level along the beam.
U.S. Pat. No. 4,680,577, is a multipurpose key switch for controlling cursor movement on a CRT display and for character entry includes a key cap that moves laterally to provide cursor control and that moves vertically for character entry.
The foregoing patents reflect the state of the art of which the applicant is aware and are tendered with the view toward discharging applicant's acknowledged duty of candor in disclosing information that may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly or when considered in combination, applicant's claimed invention.